# -*- test-case-name: twisted.words.test.test_irc -*-
# Copyright (c) 2001-2005 Twisted Matrix Laboratories.
# See LICENSE for details.


"""Internet Relay Chat Protocol for client and server.

Future Plans
============

The way the IRCClient class works here encourages people to implement
IRC clients by subclassing the ephemeral protocol class, and it tends
to end up with way more state than it should for an object which will
be destroyed as soon as the TCP transport drops.  Someone oughta do
something about that, ya know?

The DCC support needs to have more hooks for the client for it to be
able to ask the user things like \"Do you want to accept this session?\"
and \"Transfer #2 is 67% done.\" and otherwise manage the DCC sessions.

Test coverage needs to be better.

@author: U{Kevin Turner<mailto:acapnotic@twistedmatrix.com>}

@see: RFC 1459: Internet Relay Chat Protocol
@see: RFC 2812: Internet Relay Chat: Client Protocol
@see: U{The Client-To-Client-Protocol
<http://www.irchelp.org/irchelp/rfc/ctcpspec.html>}
"""

__version__ = '$Revision$'[11:-2]

from twisted.internet import reactor, protocol
from twisted.persisted import styles
from twisted.protocols import basic
from twisted.python import log, reflect, text

# System Imports

import errno
import os
import random
import re
import stat
import string
import struct
import sys
import time
import types
import traceback
import socket

from os import path

NUL = chr(0o0)
CR = chr(0o15)
NL = chr(0o12)
LF = NL
SPC = chr(0o40)

CHANNEL_PREFIXES = '&#!+'


class IRCBadMessage(Exception):
    pass


class IRCPasswordMismatch(Exception):
    pass


def parsemsg(s):
    """Breaks a message from an IRC server into its prefix, command, and arguments.
    """
    prefix = ''
    trailing = []
    if not s:
        raise IRCBadMessage("Empty line.")
    if s[0] == ':':
        prefix, s = s[1:].split(' ', 1)
    if s.find(' :') != -1:
        s, trailing = s.split(' :', 1)
        args = s.split()
        args.append(trailing)
    else:
        args = s.split()
    command = args.pop(0)
    return prefix, command, args


def split(str, length=80):
    """I break a message into multiple lines.

    I prefer to break at whitespace near str[length].  I also break at \\n.

    @returns: list of strings
    """
    if length <= 0:
        raise ValueError("Length must be a number greater than zero")
    r = []
    while len(str) > length:
        w, n = str[:length].rfind(' '), str[:length].find('\n')
        if w == -1 and n == -1:
            line, str = str[:length], str[length:]
        else:
            i = n == -1 and w or n
            line, str = str[:i], str[i + 1:]
        r.append(line)
    if len(str):
        r.extend(str.split('\n'))
    return r


class IRC(protocol.Protocol):
    """Internet Relay Chat server protocol.
    """

    buffer = ""
    hostname = None

    encoding = None

    def connectionMade(self):
        self.channels = []
        if self.hostname is None:
            self.hostname = socket.getfqdn()

    def sendLine(self, line):
        if self.encoding is not None:
            if isinstance(line, unicode):
                line = line.encode(self.encoding)
        self.transport.write("%s%s%s" % (line, CR, LF))

    def sendMessage(self, command, *parameter_list, **prefix):
        """Send a line formatted as an IRC message.

        First argument is the command, all subsequent arguments
        are parameters to that command.  If a prefix is desired,
        it may be specified with the keyword argument 'prefix'.
        """

        if not command:
            raise ValueError("IRC message requires a command.")

        if ' ' in command or command[0] == ':':
            # Not the ONLY way to screw up, but provides a little
            # sanity checking to catch likely dumb mistakes.
            raise ValueError("Somebody screwed up, 'cuz this doesn't"
                  " look like a command to me: %s" % command)

        line = string.join([command] + list(parameter_list))
        if 'prefix' in prefix:
            line = ":%s %s" % (prefix['prefix'], line)
        self.sendLine(line)

        if len(parameter_list) > 15:
            log.msg("Message has %d parameters (RFC allows 15):\n%s" %
                    (len(parameter_list), line))

    def dataReceived(self, data):
        """This hack is to support mIRC, which sends LF only,
        even though the RFC says CRLF.  (Also, the flexibility
        of LineReceiver to turn "line mode" on and off was not
        required.)
        """
        lines = (self.buffer + data).split(LF)
        # Put the (possibly empty) element after the last LF back in the
        # buffer
        self.buffer = lines.pop()

        for line in lines:
            if len(line) <= 2:
                # This is a blank line, at best.
                continue
            if line[-1] == CR:
                line = line[:-1]
            prefix, command, params = parsemsg(line)
            # mIRC is a big pile of doo-doo
            command = command.upper()
            # DEBUG: log.msg( "%s %s %s" % (prefix, command, params))

            self.handleCommand(command, prefix, params)

    def handleCommand(self, command, prefix, params):
        """Determine the function to call for the given command and call
        it with the given arguments.
        """
        method = getattr(self, "irc_%s" % command, None)
        try:
            if method is not None:
                method(prefix, params)
            else:
                self.irc_unknown(prefix, command, params)
        except:
            log.deferr()

    def irc_unknown(self, prefix, command, params):
        """Implement me!"""
        raise NotImplementedError(command, prefix, params)

    # Helper methods

    def privmsg(self, sender, recip, message):
        """Send a message to a channel or user

        @type sender: C{str} or C{unicode}
        @param sender: Who is sending this message.  Should be of the form
        username!ident@hostmask (unless you know better!).

        @type recip: C{str} or C{unicode}
        @param recip: The recipient of this message.  If a channel, it
        must start with a channel prefix.

        @type message: C{str} or C{unicode}
        @param message: The message being sent.
        """
        self.sendLine(":%s PRIVMSG %s :%s" % (sender, recip, lowQuote(message)))

    def notice(self, sender, recip, message):
        """Send a \"notice\" to a channel or user.

        Notices differ from privmsgs in that the RFC claims they are different.
        Robots are supposed to send notices and not respond to them.  Clients
        typically display notices differently from privmsgs.

        @type sender: C{str} or C{unicode}
        @param sender: Who is sending this message.  Should be of the form
        username!ident@hostmask (unless you know better!).

        @type recip: C{str} or C{unicode}
        @param recip: The recipient of this message.  If a channel, it
        must start with a channel prefix.

        @type message: C{str} or C{unicode}
        @param message: The message being sent.
        """
        self.sendLine(":%s NOTICE %s :%s" % (sender, recip, message))

    def action(self, sender, recip, message):
        """Send an action to a channel or user.

        @type sender: C{str} or C{unicode}
        @param sender: Who is sending this message.  Should be of the form
        username!ident@hostmask (unless you know better!).

        @type recip: C{str} or C{unicode}
        @param recip: The recipient of this message.  If a channel, it
        must start with a channel prefix.

        @type message: C{str} or C{unicode}
        @param message: The action being sent.
        """
        self.sendLine(":%s ACTION %s :%s" % (sender, recip, message))

    def topic(self, user, channel, topic, author=None):
        """Send the topic to a user.

        @type user: C{str} or C{unicode}
        @param user: The user receiving the topic.  Only their nick name, not
        the full hostmask.

        @type channel: C{str} or C{unicode}
        @param channel: The channel for which this is the topic.

        @type topic: C{str} or C{unicode} or C{None}
        @param topic: The topic string, unquoted, or None if there is
        no topic.

        @type author: C{str} or C{unicode}
        @param author: If the topic is being changed, the full username and hostmask
        of the person changing it.
        """
        if author is None:
            if topic is None:
                self.sendLine(':%s %s %s %s :%s' % (
                    self.hostname, RPL_NOTOPIC, user, channel, 'No topic is set.'))
            else:
                self.sendLine(":%s %s %s %s :%s" % (
                    self.hostname, RPL_TOPIC, user, channel, lowQuote(topic)))
        else:
            self.sendLine(":%s TOPIC %s :%s" % (author, channel, lowQuote(topic)))

    def topicAuthor(self, user, channel, author, date):
        """
        Send the author of and time at which a topic was set for the given
        channel.

        This sends a 333 reply message, which is not part of the IRC RFC.

        @type user: C{str} or C{unicode}
        @param user: The user receiving the topic.  Only their nick name, not
        the full hostmask.

        @type channel: C{str} or C{unicode}
        @param channel: The channel for which this information is relevant.

        @type author: C{str} or C{unicode}
        @param author: The nickname (without hostmask) of the user who last
        set the topic.

        @type date: C{int}
        @param date: A POSIX timestamp (number of seconds since the epoch)
        at which the topic was last set.
        """
        self.sendLine(':%s %d %s %s %s %d' % (
            self.hostname, 333, user, channel, author, date))

    def names(self, user, channel, names):
        """Send the names of a channel's participants to a user.

        @type user: C{str} or C{unicode}
        @param user: The user receiving the name list.  Only their nick
        name, not the full hostmask.

        @type channel: C{str} or C{unicode}
        @param channel: The channel for which this is the namelist.

        @type names: C{list} of C{str} or C{unicode}
        @param names: The names to send.
        """
        # XXX If unicode is given, these limits are not quite correct
        prefixLength = len(channel) + len(user) + 10
        namesLength = 512 - prefixLength

        L = []
        count = 0
        for n in names:
            if count + len(n) + 1 > namesLength:
                self.sendLine(":%s %s %s = %s :%s" % (
                    self.hostname, RPL_NAMREPLY, user, channel, ' '.join(L)))
                L = [n]
                count = len(n)
            else:
                L.append(n)
                count += len(n) + 1
        if L:
            self.sendLine(":%s %s %s = %s :%s" % (
                self.hostname, RPL_NAMREPLY, user, channel, ' '.join(L)))
        self.sendLine(":%s %s %s %s :End of /NAMES list" % (
            self.hostname, RPL_ENDOFNAMES, user, channel))

    def who(self, user, channel, memberInfo):
        """
        Send a list of users participating in a channel.

        @type user: C{str} or C{unicode}
        @param user: The user receiving this member information.  Only their
        nick name, not the full hostmask.

        @type channel: C{str} or C{unicode}
        @param channel: The channel for which this is the member
        information.

        @type memberInfo: C{list} of C{tuples}
        @param memberInfo: For each member of the given channel, a 7-tuple
        containing their username, their hostmask, the server to which they
        are connected, their nickname, the letter "H" or "G" (wtf do these
        mean?), the hopcount from C{user} to this member, and this member's
        real name.
        """
        for info in memberInfo:
            (username, hostmask, server, nickname, flag, hops, realName) = info
            assert flag in ("H", "G")
            self.sendLine(":%s %s %s %s %s %s %s %s %s :%d %s" % (
                self.hostname, RPL_WHOREPLY, user, channel,
                username, hostmask, server, nickname, flag, hops, realName))

        self.sendLine(":%s %s %s %s :End of /WHO list." % (
            self.hostname, RPL_ENDOFWHO, user, channel))

    def whois(self, user, nick, username, hostname, realName, server, serverInfo, oper, idle, signOn, channels):
        """
        Send information about the state of a particular user.

        @type user: C{str} or C{unicode}
        @param user: The user receiving this information.  Only their nick
        name, not the full hostmask.

        @type nick: C{str} or C{unicode}
        @param nick: The nickname of the user this information describes.

        @type username: C{str} or C{unicode}
        @param username: The user's username (eg, ident response)

        @type hostname: C{str}
        @param hostname: The user's hostmask

        @type realName: C{str} or C{unicode}
        @param realName: The user's real name

        @type server: C{str} or C{unicode}
        @param server: The name of the server to which the user is connected

        @type serverInfo: C{str} or C{unicode}
        @param serverInfo: A descriptive string about that server

        @type oper: C{bool}
        @param oper: Indicates whether the user is an IRC operator

        @type idle: C{int}
        @param idle: The number of seconds since the user last sent a message

        @type signOn: C{int}
        @param signOn: A POSIX timestamp (number of seconds since the epoch)
        indicating the time the user signed on

        @type channels: C{list} of C{str} or C{unicode}
        @param channels: A list of the channels which the user is participating in
        """
        self.sendLine(":%s %s %s %s %s %s * :%s" % (
            self.hostname, RPL_WHOISUSER, user, nick, username, hostname, realName))
        self.sendLine(":%s %s %s %s %s :%s" % (
            self.hostname, RPL_WHOISSERVER, user, nick, server, serverInfo))
        if oper:
            self.sendLine(":%s %s %s %s :is an IRC operator" % (
                self.hostname, RPL_WHOISOPERATOR, user, nick))
        self.sendLine(":%s %s %s %s %d %d :seconds idle, signon time" % (
            self.hostname, RPL_WHOISIDLE, user, nick, idle, signOn))
        self.sendLine(":%s %s %s %s :%s" % (
            self.hostname, RPL_WHOISCHANNELS, user, nick, ' '.join(channels)))
        self.sendLine(":%s %s %s %s :End of WHOIS list." % (
            self.hostname, RPL_ENDOFWHOIS, user, nick))

    def join(self, who, where):
        """Send a join message.

        @type who: C{str} or C{unicode}
        @param who: The name of the user joining.  Should be of the form
        username!ident@hostmask (unless you know better!).

        @type where: C{str} or C{unicode}
        @param where: The channel the user is joining.
        """
        self.sendLine(":%s JOIN %s" % (who, where))

    def part(self, who, where, reason=None):
        """Send a part message.

        @type who: C{str} or C{unicode}
        @param who: The name of the user joining.  Should be of the form
        username!ident@hostmask (unless you know better!).

        @type where: C{str} or C{unicode}
        @param where: The channel the user is joining.

        @type reason: C{str} or C{unicode}
        @param reason: A string describing the misery which caused
        this poor soul to depart.
        """
        if reason:
            self.sendLine(":%s PART %s :%s" % (who, where, reason))
        else:
            self.sendLine(":%s PART %s" % (who, where))

    def channelMode(self, user, channel, mode, *args):
        """
        Send information about the mode of a channel.

        @type user: C{str} or C{unicode}
        @param user: The user receiving the name list.  Only their nick
        name, not the full hostmask.

        @type channel: C{str} or C{unicode}
        @param channel: The channel for which this is the namelist.

        @type mode: C{str}
        @param mode: A string describing this channel's modes.

        @param args: Any additional arguments required by the modes.
        """
        self.sendLine(":%s %s %s %s %s %s" % (
            self.hostname, RPL_CHANNELMODEIS, user, channel, mode, ' '.join(args)))


class IRCClient(basic.LineReceiver):
    """Internet Relay Chat client protocol, with sprinkles.

    In addition to providing an interface for an IRC client protocol,
    this class also contains reasonable implementations of many common
    CTCP methods.

    TODO
    ====
     - Limit the length of messages sent (because the IRC server probably
       does).
     - Add flood protection/rate limiting for my CTCP replies.
     - NickServ cooperation.  (a mix-in?)
     - Heartbeat.  The transport may die in such a way that it does not realize
       it is dead until it is written to.  Sending something (like \"PING
       this.irc-host.net\") during idle peroids would alleviate that.  If
       you're concerned with the stability of the host as well as that of the
       transport, you might care to watch for the corresponding PONG.

    @ivar nickname: Nickname the client will use.
    @ivar password: Password used to log on to the server.  May be C{None}.
    @ivar realname: Supplied to the server during login as the \"Real name\"
        or \"ircname\".  May be C{None}.
    @ivar username: Supplied to the server during login as the \"User name\".
        May be C{None}

    @ivar userinfo: Sent in reply to a X{USERINFO} CTCP query.  If C{None}, no
        USERINFO reply will be sent.
        \"This is used to transmit a string which is settable by
        the user (and never should be set by the client).\"
    @ivar fingerReply: Sent in reply to a X{FINGER} CTCP query.  If C{None}, no
        FINGER reply will be sent.
    @type fingerReply: Callable or String

    @ivar versionName: CTCP VERSION reply, client name.  If C{None}, no VERSION
        reply will be sent.
    @ivar versionNum: CTCP VERSION reply, client version,
    @ivar versionEnv: CTCP VERSION reply, environment the client is running in.

    @ivar sourceURL: CTCP SOURCE reply, a URL where the source code of this
        client may be found.  If C{None}, no SOURCE reply will be sent.

    @ivar lineRate: Minimum delay between lines sent to the server.  If
        C{None}, no delay will be imposed.
    @type lineRate: Number of Seconds.
    """

    motd = ""
    nickname = 'irc'
    password = None
    realname = None
    username = None
    ### Responses to various CTCP queries.

    userinfo = None
    # fingerReply is a callable returning a string, or a str()able object.
    fingerReply = None
    versionName = None
    versionNum = None
    versionEnv = None

    sourceURL = "http://twistedmatrix.com/downloads/"

    dcc_destdir = '.'
    dcc_sessions = None

    # If this is false, no attempt will be made to identify
    # ourself to the server.
    performLogin = 1

    lineRate = None
    _queue = None
    _queueEmptying = None

    delimiter = '\n' # '\r\n' will also work (see dataReceived)

    __pychecker__ = 'unusednames=params,prefix,channel'

    def _reallySendLine(self, line):
        return basic.LineReceiver.sendLine(self, lowQuote(line) + '\r')

    def sendLine(self, line):
        if self.lineRate is None:
            self._reallySendLine(line)
        else:
            self._queue.append(line)
            if not self._queueEmptying:
                self._sendLine()

    def _sendLine(self):
        if self._queue:
            self._reallySendLine(self._queue.pop(0))
            self._queueEmptying = reactor.callLater(self.lineRate,
                                                    self._sendLine)
        else:
            self._queueEmptying = None

    ### Interface level client->user output methods
    ###
    ### You'll want to override these.

    ### Methods relating to the server itself

    def created(self, when):
        """Called with creation date information about the server, usually at logon.

        @type when: C{str}
        @param when: A string describing when the server was created, probably.
        """

    def yourHost(self, info):
        """Called with daemon information about the server, usually at logon.

        @type info: C{str}
        @param when: A string describing what software the server is running, probably.
        """

    def myInfo(self, servername, version, umodes, cmodes):
        """Called with information about the server, usually at logon.

        @type servername: C{str}
        @param servername: The hostname of this server.

        @type version: C{str}
        @param version: A description of what software this server runs.

        @type umodes: C{str}
        @param umodes: All the available user modes.

        @type cmodes: C{str}
        @param cmodes: All the available channel modes.
        """

    def luserClient(self, info):
        """Called with information about the number of connections, usually at logon.

        @type info: C{str}
        @param info: A description of the number of clients and servers
        connected to the network, probably.
        """

    def bounce(self, info):
        """Called with information about where the client should reconnect.

        @type info: C{str}
        @param info: A plaintext description of the address that should be
        connected to.
        """

    def isupport(self, options):
        """Called with various information about what the server supports.

        @type options: C{list} of C{str}
        @param options: Descriptions of features or limits of the server, possibly
        in the form "NAME=VALUE".
        """

    def luserChannels(self, channels):
        """Called with the number of channels existant on the server.

        @type channels: C{int}
        """

    def luserOp(self, ops):
        """Called with the number of ops logged on to the server.

        @type ops: C{int}
        """

    def luserMe(self, info):
        """Called with information about the server connected to.

        @type info: C{str}
        @param info: A plaintext string describing the number of users and servers
        connected to this server.
        """

    ### Methods involving me directly

    def privmsg(self, user, channel, message):
        """Called when I have a message from a user to me or a channel.
        """
        pass

    def joined(self, channel):
        """Called when I finish joining a channel.

        channel has the starting character (# or &) intact.
        """
        pass

    def left(self, channel):
        """Called when I have left a channel.

        channel has the starting character (# or &) intact.
        """
        pass

    def noticed(self, user, channel, message):
        """Called when I have a notice from a user to me or a channel.

        By default, this is equivalent to IRCClient.privmsg, but if your
        client makes any automated replies, you must override this!
        From the RFC::

            The difference between NOTICE and PRIVMSG is that
            automatic replies MUST NEVER be sent in response to a
            NOTICE message. [...] The object of this rule is to avoid
            loops between clients automatically sending something in
            response to something it received.
        """
        self.privmsg(user, channel, message)

    def modeChanged(self, user, channel, set, modes, args):
        """Called when a channel's modes are changed

        @type user: C{str}
        @param user: The user and hostmask which instigated this change.

        @type channel: C{str}
        @param channel: The channel for which the modes are changing.

        @type set: C{bool} or C{int}
        @param set: true if the mode is being added, false if it is being
        removed.

        @type modes: C{str}
        @param modes: The mode or modes which are being changed.

        @type args: C{tuple}
        @param args: Any additional information required for the mode
        change.
        """

    def pong(self, user, secs):
        """Called with the results of a CTCP PING query.
        """
        pass

    def signedOn(self):
        """Called after sucessfully signing on to the server.
        """
        pass

    def kickedFrom(self, channel, kicker, message):
        """Called when I am kicked from a channel.
        """
        pass

    def nickChanged(self, nick):
        """Called when my nick has been changed.
        """
        self.nickname = nick

    ### Things I observe other people doing in a channel.

    def userJoined(self, user, channel):
        """Called when I see another user joining a channel.
        """
        pass

    def userLeft(self, user, channel):
        """Called when I see another user leaving a channel.
        """
        pass

    def userQuit(self, user, quitMessage):
        """Called when I see another user disconnect from the network.
        """
        pass

    def userKicked(self, kickee, channel, kicker, message):
        """Called when I observe someone else being kicked from a channel.
        """
        pass

    def action(self, user, channel, data):
        """Called when I see a user perform an ACTION on a channel.
        """
        pass

    def topicUpdated(self, user, channel, newTopic):
        """In channel, user changed the topic to newTopic.

        Also called when first joining a channel.
        """
        pass

    def userRenamed(self, oldname, newname):
        """A user changed their name from oldname to newname.
        """
        pass

    ### Information from the server.

    def receivedMOTD(self, motd):
        """I received a message-of-the-day banner from the server.

        motd is a list of strings, where each string was sent as a seperate
        message from the server. To display, you might want to use::

            string.join(motd, '\\n')

        to get a nicely formatted string.
        """
        pass

    ### user input commands, client->server
    ### Your client will want to invoke these.

    def join(self, channel, key=None):
        if channel[0] not in '&#!+':
            channel = '#' + channel
        if key:
            self.sendLine("JOIN %s %s" % (channel, key))
        else:
            self.sendLine("JOIN %s" % (channel,))

    def leave(self, channel, reason=None):
        if channel[0] not in '&#!+':
            channel = '#' + channel
        if reason:
            self.sendLine("PART %s :%s" % (channel, reason))
        else:
            self.sendLine("PART %s" % (channel,))

    def kick(self, channel, user, reason=None):
        if channel[0] not in '&#!+':
            channel = '#' + channel
        if reason:
            self.sendLine("KICK %s %s :%s" % (channel, user, reason))
        else:
            self.sendLine("KICK %s %s" % (channel, user))

    part = leave

    def topic(self, channel, topic=None):
        """Attempt to set the topic of the given channel, or ask what it is.

        If topic is None, then I sent a topic query instead of trying to set
        the topic. The server should respond with a TOPIC message containing
        the current topic of the given channel.
        """
        # << TOPIC #xtestx :fff
        if channel[0] not in '&#!+':
            channel = '#' + channel
        if topic is not None:
            self.sendLine("TOPIC %s :%s" % (channel, topic))
        else:
            self.sendLine("TOPIC %s" % (channel,))

    def mode(self, chan, set, modes, limit=None, user=None, mask=None):
        """Change the modes on a user or channel."""
        if set:
            line = 'MODE %s +%s' % (chan, modes)
        else:
            line = 'MODE %s -%s' % (chan, modes)
        if limit is not None:
            line = '%s %d' % (line, limit)
        elif user is not None:
            line = '%s %s' % (line, user)
        elif mask is not None:
            line = '%s %s' % (line, mask)
        self.sendLine(line)

    def say(self, channel, message, length=None):
        if channel[0] not in '&#!+':
            channel = '#' + channel
        self.msg(channel, message, length)

    def msg(self, user, message, length=None):
        """Send a message to a user or channel.

        @type user: C{str}
        @param user: The username or channel name to which to direct the
        message.

        @type message: C{str}
        @param message: The text to send

        @type length: C{int}
        @param length: The maximum number of octets to send at a time.  This
        has the effect of turning a single call to msg() into multiple
        commands to the server.  This is useful when long messages may be
        sent that would otherwise cause the server to kick us off or silently
        truncate the text we are sending.  If None is passed, the entire
        message is always send in one command.
        """

        fmt = "PRIVMSG %s :%%s" % (user,)

        if length is None:
            self.sendLine(fmt % (message,))
        else:
            # NOTE: minimumLength really equals len(fmt) - 2 (for '%s') + n
            # where n is how many bytes sendLine sends to end the line.
            # n was magic numbered to 2, I think incorrectly
            minimumLength = len(fmt)
            if length <= minimumLength:
                raise ValueError("Maximum length must exceed %d for message "
                                 "to %s" % (minimumLength, user))
            lines = split(message, length - minimumLength)
            map(lambda line, self=self, fmt=fmt: self.sendLine(fmt % line),
                lines)

    def notice(self, user, message):
        self.sendLine("NOTICE %s :%s" % (user, message))

    def away(self, message=''):
        self.sendLine("AWAY :%s" % message)

    def register(self, nickname, hostname='foo', servername='bar'):
        if self.password is not None:
            self.sendLine("PASS %s" % self.password)
        self.setNick(nickname)
        if self.username is None:
            self.username = nickname
        self.sendLine("USER %s %s %s :%s" % (self.username, hostname, servername, self.realname))

    def setNick(self, nickname):
        self.nickname = nickname
        self.sendLine("NICK %s" % nickname)

    def quit(self, message=''):
        self.sendLine("QUIT :%s" % message)

    ### user input commands, client->client

    def me(self, channel, action):
        """Strike a pose.
        """
        if channel[0] not in '&#!+':
            channel = '#' + channel
        self.ctcpMakeQuery(channel, [('ACTION', action)])

    _pings = None
    _MAX_PINGRING = 12

    def ping(self, user, text=None):
        """Measure round-trip delay to another IRC client.
        """
        if self._pings is None:
            self._pings = {}

        if text is None:
            chars = string.letters + string.digits + string.punctuation
            key = ''.join([random.choice(chars) for i in range(12)])
        else:
            key = str(text)
        self._pings[(user, key)] = time.time()
        self.ctcpMakeQuery(user, [('PING', key)])

        if len(self._pings) > self._MAX_PINGRING:
            # Remove some of the oldest entries.
            byValue = [(v, k) for (k, v) in self._pings.items()]
            byValue.sort()
            excess = self._MAX_PINGRING - len(self._pings)
            for i in xrange(excess):
                del self._pings[byValue[i][1]]

    def dccSend(self, user, file):
        if type(file) == types.StringType:
            file = open(file, 'r')

        size = fileSize(file)

        name = getattr(file, "name", "file@%s" % (id(file),))

        factory = DccSendFactory(file)
        port = reactor.listenTCP(0, factory, 1)

        raise NotImplementedError(
            "XXX!!! Help!  I need to bind a socket, have it listen, and tell me its address.  "
            "(and stop accepting once we've made a single connection.)")

        my_address = struct.pack("!I", my_address)

        args = ['SEND', name, my_address, str(port)]

        if not (size is None):
            args.append(size)

        args = string.join(args, ' ')

        self.ctcpMakeQuery(user, [('DCC', args)])

    def dccResume(self, user, fileName, port, resumePos):
        """Send a DCC RESUME request to another user."""
        self.ctcpMakeQuery(user, [
            ('DCC', ['RESUME', fileName, port, resumePos])])

    def dccAcceptResume(self, user, fileName, port, resumePos):
        """Send a DCC ACCEPT response to clients who have requested a resume.
        """
        self.ctcpMakeQuery(user, [
            ('DCC', ['ACCEPT', fileName, port, resumePos])])

    ### server->client messages
    ### You might want to fiddle with these,
    ### but it is safe to leave them alone.

    def irc_ERR_NICKNAMEINUSE(self, prefix, params):
        self.register(self.nickname + '_')

    def irc_ERR_PASSWDMISMATCH(self, prefix, params):
        raise IRCPasswordMismatch("Password Incorrect.")

    def irc_RPL_WELCOME(self, prefix, params):
        self.signedOn()

    def irc_JOIN(self, prefix, params):
        nick = string.split(prefix, '!')[0]
        channel = params[-1]
        if nick == self.nickname:
            self.joined(channel)
        else:
            self.userJoined(nick, channel)

    def irc_PART(self, prefix, params):
        nick = string.split(prefix, '!')[0]
        channel = params[0]
        if nick == self.nickname:
            self.left(channel)
        else:
            self.userLeft(nick, channel)

    def irc_QUIT(self, prefix, params):
        nick = string.split(prefix, '!')[0]
        self.userQuit(nick, params[0])

    def irc_MODE(self, prefix, params):
        channel, rest = params[0], params[1:]
        set = rest[0][0] == '+'
        modes = rest[0][1:]
        args = rest[1:]
        self.modeChanged(prefix, channel, set, modes, tuple(args))

    def irc_PING(self, prefix, params):
        self.sendLine("PONG %s" % params[-1])

    def irc_PRIVMSG(self, prefix, params):
        user = prefix
        channel = params[0]
        message = params[-1]

        if not message:
            return # don't raise an exception if some idiot sends us a blank message

        if message[0] == X_DELIM:
            m = ctcpExtract(message)
            if m['extended']:
                self.ctcpQuery(user, channel, m['extended'])

            if not m['normal']:
                return

            message = string.join(m['normal'], ' ')

        self.privmsg(user, channel, message)

    def irc_NOTICE(self, prefix, params):
        user = prefix
        channel = params[0]
        message = params[-1]

        if message[0] == X_DELIM:
            m = ctcpExtract(message)
            if m['extended']:
                self.ctcpReply(user, channel, m['extended'])

            if not m['normal']:
                return

            message = string.join(m['normal'], ' ')

        self.noticed(user, channel, message)

    def irc_NICK(self, prefix, params):
        nick = string.split(prefix, '!', 1)[0]
        if nick == self.nickname:
            self.nickChanged(params[0])
        else:
            self.userRenamed(nick, params[0])

    def irc_KICK(self, prefix, params):
        """Kicked?  Who?  Not me, I hope.
        """
        kicker = string.split(prefix, '!')[0]
        channel = params[0]
        kicked = params[1]
        message = params[-1]
        if string.lower(kicked) == string.lower(self.nickname):
            # Yikes!
            self.kickedFrom(channel, kicker, message)
        else:
            self.userKicked(kicked, channel, kicker, message)

    def irc_TOPIC(self, prefix, params):
        """Someone in the channel set the topic.
        """
        user = string.split(prefix, '!')[0]
        channel = params[0]
        newtopic = params[1]
        self.topicUpdated(user, channel, newtopic)

    def irc_RPL_TOPIC(self, prefix, params):
        """I just joined the channel, and the server is telling me the current topic.
        """
        user = string.split(prefix, '!')[0]
        channel = params[1]
        newtopic = params[2]
        self.topicUpdated(user, channel, newtopic)

    def irc_RPL_NOTOPIC(self, prefix, params):
        user = string.split(prefix, '!')[0]
        channel = params[1]
        newtopic = ""
        self.topicUpdated(user, channel, newtopic)

    def irc_RPL_MOTDSTART(self, prefix, params):
        if params[-1].startswith("- "):
            params[-1] = params[-1][2:]
        self.motd = [params[-1]]

    def irc_RPL_MOTD(self, prefix, params):
        if params[-1].startswith("- "):
            params[-1] = params[-1][2:]
        self.motd.append(params[-1])

    def irc_RPL_ENDOFMOTD(self, prefix, params):
        self.receivedMOTD(self.motd)

    def irc_RPL_CREATED(self, prefix, params):
        self.created(params[1])

    def irc_RPL_YOURHOST(self, prefix, params):
        self.yourHost(params[1])

    def irc_RPL_MYINFO(self, prefix, params):
        info = params[1].split(None, 3)
        while len(info) < 4:
            info.append(None)
        self.myInfo(*info)

    def irc_RPL_BOUNCE(self, prefix, params):
        # 005 is doubly assigned.  Piece of crap dirty trash protocol.
        if params[-1] == "are available on this server":
            self.isupport(params[1:-1])
        else:
            self.bounce(params[1])

    def irc_RPL_LUSERCLIENT(self, prefix, params):
        self.luserClient(params[1])

    def irc_RPL_LUSEROP(self, prefix, params):
        try:
            self.luserOp(int(params[1]))
        except ValueError:
            pass

    def irc_RPL_LUSERCHANNELS(self, prefix, params):
        try:
            self.luserChannels(int(params[1]))
        except ValueError:
            pass

    def irc_RPL_LUSERME(self, prefix, params):
        self.luserMe(params[1])

    def irc_unknown(self, prefix, command, params):
        pass

    ### Receiving a CTCP query from another party
    ### It is safe to leave these alone.

    def ctcpQuery(self, user, channel, messages):
        """Dispatch method for any CTCP queries received.
        """
        for m in messages:
            method = getattr(self, "ctcpQuery_%s" % m[0], None)
            if method:
                method(user, channel, m[1])
            else:
                self.ctcpUnknownQuery(user, channel, m[0], m[1])

    def ctcpQuery_ACTION(self, user, channel, data):
        self.action(user, channel, data)

    def ctcpQuery_PING(self, user, channel, data):
        nick = string.split(user, "!")[0]
        self.ctcpMakeReply(nick, [("PING", data)])

    def ctcpQuery_FINGER(self, user, channel, data):
        if data is not None:
            self.quirkyMessage("Why did %s send '%s' with a FINGER query?"
                               % (user, data))
        if not self.fingerReply:
            return

        if callable(self.fingerReply):
            reply = self.fingerReply()
        else:
            reply = str(self.fingerReply)

        nick = string.split(user, "!")[0]
        self.ctcpMakeReply(nick, [('FINGER', reply)])

    def ctcpQuery_VERSION(self, user, channel, data):
        if data is not None:
            self.quirkyMessage("Why did %s send '%s' with a VERSION query?"
                               % (user, data))

        if self.versionName:
            nick = string.split(user, "!")[0]
            self.ctcpMakeReply(nick, [('VERSION', '%s:%s:%s' %
                                       (self.versionName,
                                        self.versionNum,
                                        self.versionEnv))])

    def ctcpQuery_SOURCE(self, user, channel, data):
        if data is not None:
            self.quirkyMessage("Why did %s send '%s' with a SOURCE query?"
                               % (user, data))
        if self.sourceURL:
            nick = string.split(user, "!")[0]
            # The CTCP document (Zeuge, Rollo, Mesander 1994) says that SOURCE
            # replies should be responded to with the location of an anonymous
            # FTP server in host:directory:file format.  I'm taking the liberty
            # of bringing it into the 21st century by sending a URL instead.
            self.ctcpMakeReply(nick, [('SOURCE', self.sourceURL),
                                      ('SOURCE', None)])

    def ctcpQuery_USERINFO(self, user, channel, data):
        if data is not None:
            self.quirkyMessage("Why did %s send '%s' with a USERINFO query?"
                               % (user, data))
        if self.userinfo:
            nick = string.split(user, "!")[0]
            self.ctcpMakeReply(nick, [('USERINFO', self.userinfo)])

    def ctcpQuery_CLIENTINFO(self, user, channel, data):
        """A master index of what CTCP tags this client knows.

        If no arguments are provided, respond with a list of known tags.
        If an argument is provided, provide human-readable help on
        the usage of that tag.
        """

        nick = string.split(user, "!")[0]
        if not data:
            # XXX: prefixedMethodNames gets methods from my *class*,
            # but it's entirely possible that this *instance* has more
            # methods.
            names = reflect.prefixedMethodNames(self.__class__,
                                                'ctcpQuery_')

            self.ctcpMakeReply(nick, [('CLIENTINFO',
                                       string.join(names, ' '))])
        else:
            args = string.split(data)
            method = getattr(self, 'ctcpQuery_%s' % (args[0],), None)
            if not method:
                self.ctcpMakeReply(nick, [('ERRMSG',
                                           "CLIENTINFO %s :"
                                           "Unknown query '%s'"
                                           % (data, args[0]))])
                return
            doc = getattr(method, '__doc__', '')
            self.ctcpMakeReply(nick, [('CLIENTINFO', doc)])

    def ctcpQuery_ERRMSG(self, user, channel, data):
        # Yeah, this seems strange, but that's what the spec says to do
        # when faced with an ERRMSG query (not a reply).
        nick = string.split(user, "!")[0]
        self.ctcpMakeReply(nick, [('ERRMSG',
                                   "%s :No error has occoured." % data)])

    def ctcpQuery_TIME(self, user, channel, data):
        if data is not None:
            self.quirkyMessage("Why did %s send '%s' with a TIME query?"
                               % (user, data))
        nick = string.split(user, "!")[0]
        self.ctcpMakeReply(nick,
                           [('TIME', ':%s' %
                             time.asctime(time.localtime(time.time())))])

    def ctcpQuery_DCC(self, user, channel, data):
        """Initiate a Direct Client Connection
        """

        if not data:
            return
        dcctype = data.split(None, 1)[0].upper()
        handler = getattr(self, "dcc_" + dcctype, None)
        if handler:
            if self.dcc_sessions is None:
                self.dcc_sessions = []
            data = data[len(dcctype) + 1:]
            handler(user, channel, data)
        else:
            nick = string.split(user, "!")[0]
            self.ctcpMakeReply(nick, [('ERRMSG',
                                       "DCC %s :Unknown DCC type '%s'"
                                       % (data, dcctype))])
            self.quirkyMessage("%s offered unknown DCC type %s"
                               % (user, dcctype))

    def dcc_SEND(self, user, channel, data):
        # Use splitQuoted for those who send files with spaces in the names.
        data = text.splitQuoted(data)
        if len(data) < 3:
            raise IRCBadMessage("malformed DCC SEND request: %r" % (data,))

        (filename, address, port) = data[:3]

        address = dccParseAddress(address)
        try:
            port = int(port)
        except ValueError:
            raise IRCBadMessage("Indecipherable port %r" % (port,))

        size = -1
        if len(data) >= 4:
            try:
                size = int(data[3])
            except ValueError:
                pass

        # XXX Should we bother passing this data?
        self.dccDoSend(user, address, port, filename, size, data)

    def dcc_ACCEPT(self, user, channel, data):
        data = text.splitQuoted(data)
        if len(data) < 3:
            raise IRCBadMessage("malformed DCC SEND ACCEPT request: %r" % (data,))
        (filename, port, resumePos) = data[:3]
        try:
            port = int(port)
            resumePos = int(resumePos)
        except ValueError:
            return

        self.dccDoAcceptResume(user, filename, port, resumePos)

    def dcc_RESUME(self, user, channel, data):
        data = text.splitQuoted(data)
        if len(data) < 3:
            raise IRCBadMessage("malformed DCC SEND RESUME request: %r" % (data,))
        (filename, port, resumePos) = data[:3]
        try:
            port = int(port)
            resumePos = int(resumePos)
        except ValueError:
            return
        self.dccDoResume(user, filename, port, resumePos)

    def dcc_CHAT(self, user, channel, data):
        data = text.splitQuoted(data)
        if len(data) < 3:
            raise IRCBadMessage("malformed DCC CHAT request: %r" % (data,))

        (filename, address, port) = data[:3]

        address = dccParseAddress(address)
        try:
            port = int(port)
        except ValueError:
            raise IRCBadMessage("Indecipherable port %r" % (port,))

        self.dccDoChat(user, channel, address, port, data)

    ### The dccDo methods are the slightly higher-level siblings of
    ### common dcc_ methods; the arguments have been parsed for them.

    def dccDoSend(self, user, address, port, fileName, size, data):
        """Called when I receive a DCC SEND offer from a client.

        By default, I do nothing here."""
        ## filename = path.basename(arg)
        ## protocol = DccFileReceive(filename, size,
        ##                           (user,channel,data),self.dcc_destdir)
        ## reactor.clientTCP(address, port, protocol)
        ## self.dcc_sessions.append(protocol)
        pass

    def dccDoResume(self, user, file, port, resumePos):
        """Called when a client is trying to resume an offered file
        via DCC send.  It should be either replied to with a DCC
        ACCEPT or ignored (default)."""
        pass

    def dccDoAcceptResume(self, user, file, port, resumePos):
        """Called when a client has verified and accepted a DCC resume
        request made by us.  By default it will do nothing."""
        pass

    def dccDoChat(self, user, channel, address, port, data):
        pass
        #factory = DccChatFactory(self, queryData=(user, channel, data))
        #reactor.connectTCP(address, port, factory)
        #self.dcc_sessions.append(factory)

    #def ctcpQuery_SED(self, user, data):
    #    """Simple Encryption Doodoo
    #
    #    Feel free to implement this, but no specification is available.
    #    """
    #    raise NotImplementedError

    def ctcpUnknownQuery(self, user, channel, tag, data):
        nick = string.split(user, "!")[0]
        self.ctcpMakeReply(nick, [('ERRMSG',
                                   "%s %s: Unknown query '%s'"
                                   % (tag, data, tag))])

        log.msg("Unknown CTCP query from %s: %s %s\n"
                 % (user, tag, data))

    def ctcpMakeReply(self, user, messages):
        """Send one or more X{extended messages} as a CTCP reply.

        @type messages: a list of extended messages.  An extended
        message is a (tag, data) tuple, where 'data' may be C{None}.
        """
        self.notice(user, ctcpStringify(messages))

    ### client CTCP query commands

    def ctcpMakeQuery(self, user, messages):
        """Send one or more X{extended messages} as a CTCP query.

        @type messages: a list of extended messages.  An extended
        message is a (tag, data) tuple, where 'data' may be C{None}.
        """
        self.msg(user, ctcpStringify(messages))

    ### Receiving a response to a CTCP query (presumably to one we made)
    ### You may want to add methods here, or override UnknownReply.

    def ctcpReply(self, user, channel, messages):
        """Dispatch method for any CTCP replies received.
        """
        for m in messages:
            method = getattr(self, "ctcpReply_%s" % m[0], None)
            if method:
                method(user, channel, m[1])
            else:
                self.ctcpUnknownReply(user, channel, m[0], m[1])

    def ctcpReply_PING(self, user, channel, data):
        nick = user.split('!', 1)[0]
        if (not self._pings) or ((nick, data) not in self._pings):
            raise IRCBadMessage("Bogus PING response from %s: %s" % (user, data))

        t0 = self._pings[(nick, data)]
        self.pong(user, time.time() - t0)

    def ctcpUnknownReply(self, user, channel, tag, data):
        """Called when a fitting ctcpReply_ method is not found.

        XXX: If the client makes arbitrary CTCP queries,
        this method should probably show the responses to
        them instead of treating them as anomolies.
        """
        log.msg("Unknown CTCP reply from %s: %s %s\n"
                 % (user, tag, data))

    ### Error handlers
    ### You may override these with something more appropriate to your UI.

    def badMessage(self, line, excType, excValue, tb):
        """When I get a message that's so broken I can't use it.
        """
        log.msg(line)
        log.msg(string.join(traceback.format_exception(excType,
                                                        excValue,
                                                        tb), ''))

    def quirkyMessage(self, s):
        """This is called when I receive a message which is peculiar,
        but not wholly indecipherable.
        """
        log.msg(s + '\n')

    ### Protocool methods

    def connectionMade(self):
        self._queue = []
        if self.performLogin:
            self.register(self.nickname)

    def dataReceived(self, data):
        basic.LineReceiver.dataReceived(self, data.replace('\r', ''))

    def lineReceived(self, line):
        line = lowDequote(line)
        try:
            prefix, command, params = parsemsg(line)
            if command in numeric_to_symbolic:
                command = numeric_to_symbolic[command]
            self.handleCommand(command, prefix, params)
        except IRCBadMessage:
            self.badMessage(line, *sys.exc_info())

    def handleCommand(self, command, prefix, params):
        """Determine the function to call for the given command and call
        it with the given arguments.
        """
        method = getattr(self, "irc_%s" % command, None)
        try:
            if method is not None:
                method(prefix, params)
            else:
                self.irc_unknown(prefix, command, params)
        except:
            log.deferr()

    def __getstate__(self):
        dct = self.__dict__.copy()
        dct['dcc_sessions'] = None
        dct['_pings'] = None
        return dct


def dccParseAddress(address):
    if '.' in address:
        pass
    else:
        try:
            address = long(address)
        except ValueError:
            raise IRCBadMessage("Indecipherable address %r" % (address,))
        else:
            address = (
                (address >> 24) & 0xFF,
                (address >> 16) & 0xFF,
                (address >> 8) & 0xFF,
                address & 0xFF,
                )
            address = '.'.join(map(str, address))
    return address


class DccFileReceiveBasic(protocol.Protocol, styles.Ephemeral):
    """Bare protocol to receive a Direct Client Connection SEND stream.

    This does enough to keep the other guy talking, but you'll want to
    extend my dataReceived method to *do* something with the data I get.
    """

    bytesReceived = 0

    def __init__(self, resumeOffset=0):
        self.bytesReceived = resumeOffset
        self.resume = (resumeOffset != 0)

    def dataReceived(self, data):
        """Called when data is received.

        Warning: This just acknowledges to the remote host that the
        data has been received; it doesn't *do* anything with the
        data, so you'll want to override this.
        """
        self.bytesReceived = self.bytesReceived + len(data)
        self.transport.write(struct.pack('!i', self.bytesReceived))


class DccSendProtocol(protocol.Protocol, styles.Ephemeral):
    """Protocol for an outgoing Direct Client Connection SEND.
    """

    blocksize = 1024
    file = None
    bytesSent = 0
    completed = 0
    connected = 0

    def __init__(self, file):
        if type(file) is types.StringType:
            self.file = open(file, 'r')

    def connectionMade(self):
        self.connected = 1
        self.sendBlock()

    def dataReceived(self, data):
        # XXX: Do we need to check to see if len(data) != fmtsize?

        bytesShesGot = struct.unpack("!I", data)
        if bytesShesGot < self.bytesSent:
            # Wait for her.
            # XXX? Add some checks to see if we've stalled out?
            return
        elif bytesShesGot > self.bytesSent:
            # self.transport.log("DCC SEND %s: She says she has %d bytes "
            #                    "but I've only sent %d.  I'm stopping "
            #                    "this screwy transfer."
            #                    % (self.file,
            #                       bytesShesGot, self.bytesSent))
            self.transport.loseConnection()
            return

        self.sendBlock()

    def sendBlock(self):
        block = self.file.read(self.blocksize)
        if block:
            self.transport.write(block)
            self.bytesSent = self.bytesSent + len(block)
        else:
            # Nothing more to send, transfer complete.
            self.transport.loseConnection()
            self.completed = 1

    def connectionLost(self, reason):
        self.connected = 0
        if hasattr(self.file, "close"):
            self.file.close()


class DccSendFactory(protocol.Factory):
    protocol = DccSendProtocol

    def __init__(self, file):
        self.file = file

    def buildProtocol(self, connection):
        p = self.protocol(self.file)
        p.factory = self
        return p


def fileSize(file):
    """I'll try my damndest to determine the size of this file object.
    """
    size = None
    if hasattr(file, "fileno"):
        fileno = file.fileno()
        try:
            stat_ = os.fstat(fileno)
            size = stat_[stat.ST_SIZE]
        except:
            pass
        else:
            return size

    if hasattr(file, "name") and path.exists(file.name):
        try:
            size = path.getsize(file.name)
        except:
            pass
        else:
            return size

    if hasattr(file, "seek") and hasattr(file, "tell"):
        try:
            try:
                file.seek(0, 2)
                size = file.tell()
            finally:
                file.seek(0, 0)
        except:
            pass
        else:
            return size

    return size


class DccChat(basic.LineReceiver, styles.Ephemeral):
    """Direct Client Connection protocol type CHAT.

    DCC CHAT is really just your run o' the mill basic.LineReceiver
    protocol.  This class only varies from that slightly, accepting
    either LF or CR LF for a line delimeter for incoming messages
    while always using CR LF for outgoing.

    The lineReceived method implemented here uses the DCC connection's
    'client' attribute (provided upon construction) to deliver incoming
    lines from the DCC chat via IRCClient's normal privmsg interface.
    That's something of a spoof, which you may well want to override.
    """

    queryData = None
    delimiter = CR + NL
    client = None
    remoteParty = None
    buffer = ""

    def __init__(self, client, queryData=None):
        """Initialize a new DCC CHAT session.

        queryData is a 3-tuple of
        (fromUser, targetUserOrChannel, data)
        as received by the CTCP query.

        (To be honest, fromUser is the only thing that's currently
        used here. targetUserOrChannel is potentially useful, while
        the 'data' argument is soley for informational purposes.)
        """
        self.client = client
        if queryData:
            self.queryData = queryData
            self.remoteParty = self.queryData[0]

    def dataReceived(self, data):
        self.buffer = self.buffer + data
        lines = string.split(self.buffer, LF)
        # Put the (possibly empty) element after the last LF back in the
        # buffer
        self.buffer = lines.pop()

        for line in lines:
            if line[-1] == CR:
                line = line[:-1]
            self.lineReceived(line)

    def lineReceived(self, line):
        log.msg("DCC CHAT<%s> %s" % (self.remoteParty, line))
        self.client.privmsg(self.remoteParty,
                            self.client.nickname, line)


class DccChatFactory(protocol.ClientFactory):
    protocol = DccChat
    noisy = 0

    def __init__(self, client, queryData):
        self.client = client
        self.queryData = queryData

    def buildProtocol(self, addr):
        p = self.protocol(client=self.client, queryData=self.queryData)
        p.factory = self

    def clientConnectionFailed(self, unused_connector, unused_reason):
        self.client.dcc_sessions.remove(self)

    def clientConnectionLost(self, unused_connector, unused_reason):
        self.client.dcc_sessions.remove(self)


def dccDescribe(data):
    """Given the data chunk from a DCC query, return a descriptive string.
    """

    orig_data = data
    data = string.split(data)
    if len(data) < 4:
        return orig_data

    (dcctype, arg, address, port) = data[:4]

    if '.' in address:
        pass
    else:
        try:
            address = long(address)
        except ValueError:
            pass
        else:
            address = (
                (address >> 24) & 0xFF,
                (address >> 16) & 0xFF,
                (address >> 8) & 0xFF,
                address & 0xFF,
                )
            # The mapping to 'int' is to get rid of those accursed
            # "L"s which python 1.5.2 puts on the end of longs.
            address = string.join(map(str, map(int, address)), ".")

    if dcctype == 'SEND':
        filename = arg

        size_txt = ''
        if len(data) >= 5:
            try:
                size = int(data[4])
                size_txt = ' of size %d bytes' % (size,)
            except ValueError:
                pass

        dcc_text = ("SEND for file '%s'%s at host %s, port %s"
                    % (filename, size_txt, address, port))
    elif dcctype == 'CHAT':
        dcc_text = ("CHAT for host %s, port %s"
                    % (address, port))
    else:
        dcc_text = orig_data

    return dcc_text


class DccFileReceive(DccFileReceiveBasic):
    """Higher-level coverage for getting a file from DCC SEND.

    I allow you to change the file's name and destination directory.
    I won't overwrite an existing file unless I've been told it's okay
    to do so. If passed the resumeOffset keyword argument I will attempt to
    resume the file from that amount of bytes.

    XXX: I need to let the client know when I am finished.
    XXX: I need to decide how to keep a progress indicator updated.
    XXX: Client needs a way to tell me \"Do not finish until I say so.\"
    XXX: I need to make sure the client understands if the file cannot be written.
    """

    filename = 'dcc'
    fileSize = -1
    destDir = '.'
    overwrite = 0
    fromUser = None
    queryData = None

    def __init__(self, filename, fileSize=-1, queryData=None,
                 destDir='.', resumeOffset=0):
        DccFileReceiveBasic.__init__(self, resumeOffset=resumeOffset)
        self.filename = filename
        self.destDir = destDir
        self.fileSize = fileSize

        if queryData:
            self.queryData = queryData
            self.fromUser = self.queryData[0]

    def set_directory(self, directory):
        """Set the directory where the downloaded file will be placed.

        May raise OSError if the supplied directory path is not suitable.
        """
        if not path.exists(directory):
            raise OSError(errno.ENOENT, "You see no directory there.",
                          directory)
        if not path.isdir(directory):
            raise OSError(errno.ENOTDIR, "You cannot put a file into "
                          "something which is not a directory.",
                          directory)
        if not os.access(directory, os.X_OK | os.W_OK):
            raise OSError(errno.EACCES,
                          "This directory is too hard to write in to.",
                          directory)
        self.destDir = directory

    def set_filename(self, filename):
        """Change the name of the file being transferred.

        This replaces the file name provided by the sender.
        """
        self.filename = filename

    def set_overwrite(self, boolean):
        """May I overwrite existing files?
        """
        self.overwrite = boolean

    # Protocol-level methods.

    def connectionMade(self):
        dst = path.abspath(path.join(self.destDir, self.filename))
        exists = path.exists(dst)
        if self.resume and exists:
            # I have been told I want to resume, and a file already
            # exists - Here we go
            self.file = open(dst, 'ab')
            log.msg("Attempting to resume %s - starting from %d bytes" %
                    (self.file, self.file.tell()))
        elif self.overwrite or not exists:
            self.file = open(dst, 'wb')
        else:
            raise OSError(errno.EEXIST,
                          "There's a file in the way.  "
                          "Perhaps that's why you cannot open it.",
                          dst)

    def dataReceived(self, data):
        self.file.write(data)
        DccFileReceiveBasic.dataReceived(self, data)

        # XXX: update a progress indicator here?

    def connectionLost(self, reason):
        """When the connection is lost, I close the file.
        """
        self.connected = 0
        logmsg = ("%s closed." % (self,))
        if self.fileSize > 0:
            logmsg = ("%s  %d/%d bytes received"
                      % (logmsg, self.bytesReceived, self.fileSize))
            if self.bytesReceived == self.fileSize:
                pass # Hooray!
            elif self.bytesReceived < self.fileSize:
                logmsg = ("%s (Warning: %d bytes short)"
                          % (logmsg, self.fileSize - self.bytesReceived))
            else:
                logmsg = ("%s (file larger than expected)"
                          % (logmsg,))
        else:
            logmsg = ("%s  %d bytes received"
                      % (logmsg, self.bytesReceived))

        if hasattr(self, 'file'):
            logmsg = "%s and written to %s.\n" % (logmsg, self.file.name)
            if hasattr(self.file, 'close'):
                self.file.close()

        # self.transport.log(logmsg)

    def __str__(self):
        if not self.connected:
            return "<Unconnected DccFileReceive object at %x>" % (id(self),)
        from_ = self.transport.getPeer()
        if self.fromUser:
            from_ = "%s (%s)" % (self.fromUser, from_)

        s = ("DCC transfer of '%s' from %s" % (self.filename, from_))
        return s

    def __repr__(self):
        s = ("<%s at %x: GET %s>"
             % (self.__class__, id(self), self.filename))
        return s


# CTCP constants and helper functions

X_DELIM = chr(0o1)


def ctcpExtract(message):
    """Extract CTCP data from a string.

    Returns a dictionary with two items:

       - C{'extended'}: a list of CTCP (tag, data) tuples
       - C{'normal'}: a list of strings which were not inside a CTCP delimeter
    """

    extended_messages = []
    normal_messages = []
    retval = {'extended': extended_messages,
              'normal': normal_messages}

    messages = string.split(message, X_DELIM)
    odd = 0

    # X1 extended data X2 nomal data X3 extended data X4 normal...
    while messages:
        if odd:
            extended_messages.append(messages.pop(0))
        else:
            normal_messages.append(messages.pop(0))
        odd = not odd

    extended_messages[:] = filter(None, extended_messages)
    normal_messages[:] = filter(None, normal_messages)

    extended_messages[:] = map(ctcpDequote, extended_messages)
    for i in xrange(len(extended_messages)):
        m = string.split(extended_messages[i], SPC, 1)
        tag = m[0]
        if len(m) > 1:
            data = m[1]
        else:
            data = None

        extended_messages[i] = (tag, data)

    return retval

# CTCP escaping


M_QUOTE = chr(0o20)

mQuoteTable = {
    NUL: M_QUOTE + '0',
    NL: M_QUOTE + 'n',
    CR: M_QUOTE + 'r',
    M_QUOTE: M_QUOTE + M_QUOTE
    }

mDequoteTable = {}
for k, v in mQuoteTable.items():
    mDequoteTable[v[-1]] = k
del k, v

mEscape_re = re.compile('%s.' % (re.escape(M_QUOTE),), re.DOTALL)


def lowQuote(s):
    for c in (M_QUOTE, NUL, NL, CR):
        s = string.replace(s, c, mQuoteTable[c])
    return s


def lowDequote(s):
    def sub(matchobj, mDequoteTable=mDequoteTable):
        s = matchobj.group()[1]
        try:
            s = mDequoteTable[s]
        except KeyError:
            s = s
        return s

    return mEscape_re.sub(sub, s)


X_QUOTE = '\\'

xQuoteTable = {
    X_DELIM: X_QUOTE + 'a',
    X_QUOTE: X_QUOTE + X_QUOTE
    }

xDequoteTable = {}

for k, v in xQuoteTable.items():
    xDequoteTable[v[-1]] = k

xEscape_re = re.compile('%s.' % (re.escape(X_QUOTE),), re.DOTALL)


def ctcpQuote(s):
    for c in (X_QUOTE, X_DELIM):
        s = string.replace(s, c, xQuoteTable[c])
    return s


def ctcpDequote(s):
    def sub(matchobj, xDequoteTable=xDequoteTable):
        s = matchobj.group()[1]
        try:
            s = xDequoteTable[s]
        except KeyError:
            s = s
        return s

    return xEscape_re.sub(sub, s)


def ctcpStringify(messages):
    """
    @type messages: a list of extended messages.  An extended
    message is a (tag, data) tuple, where 'data' may be C{None}, a
    string, or a list of strings to be joined with whitespace.

    @returns: String
    """
    coded_messages = []
    for (tag, data) in messages:
        if data:
            if not isinstance(data, types.StringType):
                try:
                    # data as list-of-strings
                    data = " ".join(map(str, data))
                except TypeError:
                    # No?  Then use it's %s representation.
                    pass
            m = "%s %s" % (tag, data)
        else:
            m = str(tag)
        m = ctcpQuote(m)
        m = "%s%s%s" % (X_DELIM, m, X_DELIM)
        coded_messages.append(m)

    line = string.join(coded_messages, '')
    return line


# Constants (from RFC 2812)
RPL_WELCOME = '001'
RPL_YOURHOST = '002'
RPL_CREATED = '003'
RPL_MYINFO = '004'
RPL_BOUNCE = '005'
RPL_USERHOST = '302'
RPL_ISON = '303'
RPL_AWAY = '301'
RPL_UNAWAY = '305'
RPL_NOWAWAY = '306'
RPL_WHOISUSER = '311'
RPL_WHOISSERVER = '312'
RPL_WHOISOPERATOR = '313'
RPL_WHOISIDLE = '317'
RPL_ENDOFWHOIS = '318'
RPL_WHOISCHANNELS = '319'
RPL_WHOWASUSER = '314'
RPL_ENDOFWHOWAS = '369'
RPL_LISTSTART = '321'
RPL_LIST = '322'
RPL_LISTEND = '323'
RPL_UNIQOPIS = '325'
RPL_CHANNELMODEIS = '324'
RPL_NOTOPIC = '331'
RPL_TOPIC = '332'
RPL_INVITING = '341'
RPL_SUMMONING = '342'
RPL_INVITELIST = '346'
RPL_ENDOFINVITELIST = '347'
RPL_EXCEPTLIST = '348'
RPL_ENDOFEXCEPTLIST = '349'
RPL_VERSION = '351'
RPL_WHOREPLY = '352'
RPL_ENDOFWHO = '315'
RPL_NAMREPLY = '353'
RPL_ENDOFNAMES = '366'
RPL_LINKS = '364'
RPL_ENDOFLINKS = '365'
RPL_BANLIST = '367'
RPL_ENDOFBANLIST = '368'
RPL_INFO = '371'
RPL_ENDOFINFO = '374'
RPL_MOTDSTART = '375'
RPL_MOTD = '372'
RPL_ENDOFMOTD = '376'
RPL_YOUREOPER = '381'
RPL_REHASHING = '382'
RPL_YOURESERVICE = '383'
RPL_TIME = '391'
RPL_USERSSTART = '392'
RPL_USERS = '393'
RPL_ENDOFUSERS = '394'
RPL_NOUSERS = '395'
RPL_TRACELINK = '200'
RPL_TRACECONNECTING = '201'
RPL_TRACEHANDSHAKE = '202'
RPL_TRACEUNKNOWN = '203'
RPL_TRACEOPERATOR = '204'
RPL_TRACEUSER = '205'
RPL_TRACESERVER = '206'
RPL_TRACESERVICE = '207'
RPL_TRACENEWTYPE = '208'
RPL_TRACECLASS = '209'
RPL_TRACERECONNECT = '210'
RPL_TRACELOG = '261'
RPL_TRACEEND = '262'
RPL_STATSLINKINFO = '211'
RPL_STATSCOMMANDS = '212'
RPL_ENDOFSTATS = '219'
RPL_STATSUPTIME = '242'
RPL_STATSOLINE = '243'
RPL_UMODEIS = '221'
RPL_SERVLIST = '234'
RPL_SERVLISTEND = '235'
RPL_LUSERCLIENT = '251'
RPL_LUSEROP = '252'
RPL_LUSERUNKNOWN = '253'
RPL_LUSERCHANNELS = '254'
RPL_LUSERME = '255'
RPL_ADMINME = '256'
RPL_ADMINLOC = '257'
RPL_ADMINLOC = '258'
RPL_ADMINEMAIL = '259'
RPL_TRYAGAIN = '263'
ERR_NOSUCHNICK = '401'
ERR_NOSUCHSERVER = '402'
ERR_NOSUCHCHANNEL = '403'
ERR_CANNOTSENDTOCHAN = '404'
ERR_TOOMANYCHANNELS = '405'
ERR_WASNOSUCHNICK = '406'
ERR_TOOMANYTARGETS = '407'
ERR_NOSUCHSERVICE = '408'
ERR_NOORIGIN = '409'
ERR_NORECIPIENT = '411'
ERR_NOTEXTTOSEND = '412'
ERR_NOTOPLEVEL = '413'
ERR_WILDTOPLEVEL = '414'
ERR_BADMASK = '415'
ERR_UNKNOWNCOMMAND = '421'
ERR_NOMOTD = '422'
ERR_NOADMININFO = '423'
ERR_FILEERROR = '424'
ERR_NONICKNAMEGIVEN = '431'
ERR_ERRONEUSNICKNAME = '432'
ERR_NICKNAMEINUSE = '433'
ERR_NICKCOLLISION = '436'
ERR_UNAVAILRESOURCE = '437'
ERR_USERNOTINCHANNEL = '441'
ERR_NOTONCHANNEL = '442'
ERR_USERONCHANNEL = '443'
ERR_NOLOGIN = '444'
ERR_SUMMONDISABLED = '445'
ERR_USERSDISABLED = '446'
ERR_NOTREGISTERED = '451'
ERR_NEEDMOREPARAMS = '461'
ERR_ALREADYREGISTRED = '462'
ERR_NOPERMFORHOST = '463'
ERR_PASSWDMISMATCH = '464'
ERR_YOUREBANNEDCREEP = '465'
ERR_YOUWILLBEBANNED = '466'
ERR_KEYSET = '467'
ERR_CHANNELISFULL = '471'
ERR_UNKNOWNMODE = '472'
ERR_INVITEONLYCHAN = '473'
ERR_BANNEDFROMCHAN = '474'
ERR_BADCHANNELKEY = '475'
ERR_BADCHANMASK = '476'
ERR_NOCHANMODES = '477'
ERR_BANLISTFULL = '478'
ERR_NOPRIVILEGES = '481'
ERR_CHANOPRIVSNEEDED = '482'
ERR_CANTKILLSERVER = '483'
ERR_RESTRICTED = '484'
ERR_UNIQOPPRIVSNEEDED = '485'
ERR_NOOPERHOST = '491'
ERR_NOSERVICEHOST = '492'
ERR_UMODEUNKNOWNFLAG = '501'
ERR_USERSDONTMATCH = '502'

# And hey, as long as the strings are already intern'd...
symbolic_to_numeric = {
    "RPL_WELCOME": '001',
    "RPL_YOURHOST": '002',
    "RPL_CREATED": '003',
    "RPL_MYINFO": '004',
    "RPL_BOUNCE": '005',
    "RPL_USERHOST": '302',
    "RPL_ISON": '303',
    "RPL_AWAY": '301',
    "RPL_UNAWAY": '305',
    "RPL_NOWAWAY": '306',
    "RPL_WHOISUSER": '311',
    "RPL_WHOISSERVER": '312',
    "RPL_WHOISOPERATOR": '313',
    "RPL_WHOISIDLE": '317',
    "RPL_ENDOFWHOIS": '318',
    "RPL_WHOISCHANNELS": '319',
    "RPL_WHOWASUSER": '314',
    "RPL_ENDOFWHOWAS": '369',
    "RPL_LISTSTART": '321',
    "RPL_LIST": '322',
    "RPL_LISTEND": '323',
    "RPL_UNIQOPIS": '325',
    "RPL_CHANNELMODEIS": '324',
    "RPL_NOTOPIC": '331',
    "RPL_TOPIC": '332',
    "RPL_INVITING": '341',
    "RPL_SUMMONING": '342',
    "RPL_INVITELIST": '346',
    "RPL_ENDOFINVITELIST": '347',
    "RPL_EXCEPTLIST": '348',
    "RPL_ENDOFEXCEPTLIST": '349',
    "RPL_VERSION": '351',
    "RPL_WHOREPLY": '352',
    "RPL_ENDOFWHO": '315',
    "RPL_NAMREPLY": '353',
    "RPL_ENDOFNAMES": '366',
    "RPL_LINKS": '364',
    "RPL_ENDOFLINKS": '365',
    "RPL_BANLIST": '367',
    "RPL_ENDOFBANLIST": '368',
    "RPL_INFO": '371',
    "RPL_ENDOFINFO": '374',
    "RPL_MOTDSTART": '375',
    "RPL_MOTD": '372',
    "RPL_ENDOFMOTD": '376',
    "RPL_YOUREOPER": '381',
    "RPL_REHASHING": '382',
    "RPL_YOURESERVICE": '383',
    "RPL_TIME": '391',
    "RPL_USERSSTART": '392',
    "RPL_USERS": '393',
    "RPL_ENDOFUSERS": '394',
    "RPL_NOUSERS": '395',
    "RPL_TRACELINK": '200',
    "RPL_TRACECONNECTING": '201',
    "RPL_TRACEHANDSHAKE": '202',
    "RPL_TRACEUNKNOWN": '203',
    "RPL_TRACEOPERATOR": '204',
    "RPL_TRACEUSER": '205',
    "RPL_TRACESERVER": '206',
    "RPL_TRACESERVICE": '207',
    "RPL_TRACENEWTYPE": '208',
    "RPL_TRACECLASS": '209',
    "RPL_TRACERECONNECT": '210',
    "RPL_TRACELOG": '261',
    "RPL_TRACEEND": '262',
    "RPL_STATSLINKINFO": '211',
    "RPL_STATSCOMMANDS": '212',
    "RPL_ENDOFSTATS": '219',
    "RPL_STATSUPTIME": '242',
    "RPL_STATSOLINE": '243',
    "RPL_UMODEIS": '221',
    "RPL_SERVLIST": '234',
    "RPL_SERVLISTEND": '235',
    "RPL_LUSERCLIENT": '251',
    "RPL_LUSEROP": '252',
    "RPL_LUSERUNKNOWN": '253',
    "RPL_LUSERCHANNELS": '254',
    "RPL_LUSERME": '255',
    "RPL_ADMINME": '256',
    "RPL_ADMINLOC": '257',
    "RPL_ADMINLOC": '258',
    "RPL_ADMINEMAIL": '259',
    "RPL_TRYAGAIN": '263',
    "ERR_NOSUCHNICK": '401',
    "ERR_NOSUCHSERVER": '402',
    "ERR_NOSUCHCHANNEL": '403',
    "ERR_CANNOTSENDTOCHAN": '404',
    "ERR_TOOMANYCHANNELS": '405',
    "ERR_WASNOSUCHNICK": '406',
    "ERR_TOOMANYTARGETS": '407',
    "ERR_NOSUCHSERVICE": '408',
    "ERR_NOORIGIN": '409',
    "ERR_NORECIPIENT": '411',
    "ERR_NOTEXTTOSEND": '412',
    "ERR_NOTOPLEVEL": '413',
    "ERR_WILDTOPLEVEL": '414',
    "ERR_BADMASK": '415',
    "ERR_UNKNOWNCOMMAND": '421',
    "ERR_NOMOTD": '422',
    "ERR_NOADMININFO": '423',
    "ERR_FILEERROR": '424',
    "ERR_NONICKNAMEGIVEN": '431',
    "ERR_ERRONEUSNICKNAME": '432',
    "ERR_NICKNAMEINUSE": '433',
    "ERR_NICKCOLLISION": '436',
    "ERR_UNAVAILRESOURCE": '437',
    "ERR_USERNOTINCHANNEL": '441',
    "ERR_NOTONCHANNEL": '442',
    "ERR_USERONCHANNEL": '443',
    "ERR_NOLOGIN": '444',
    "ERR_SUMMONDISABLED": '445',
    "ERR_USERSDISABLED": '446',
    "ERR_NOTREGISTERED": '451',
    "ERR_NEEDMOREPARAMS": '461',
    "ERR_ALREADYREGISTRED": '462',
    "ERR_NOPERMFORHOST": '463',
    "ERR_PASSWDMISMATCH": '464',
    "ERR_YOUREBANNEDCREEP": '465',
    "ERR_YOUWILLBEBANNED": '466',
    "ERR_KEYSET": '467',
    "ERR_CHANNELISFULL": '471',
    "ERR_UNKNOWNMODE": '472',
    "ERR_INVITEONLYCHAN": '473',
    "ERR_BANNEDFROMCHAN": '474',
    "ERR_BADCHANNELKEY": '475',
    "ERR_BADCHANMASK": '476',
    "ERR_NOCHANMODES": '477',
    "ERR_BANLISTFULL": '478',
    "ERR_NOPRIVILEGES": '481',
    "ERR_CHANOPRIVSNEEDED": '482',
    "ERR_CANTKILLSERVER": '483',
    "ERR_RESTRICTED": '484',
    "ERR_UNIQOPPRIVSNEEDED": '485',
    "ERR_NOOPERHOST": '491',
    "ERR_NOSERVICEHOST": '492',
    "ERR_UMODEUNKNOWNFLAG": '501',
    "ERR_USERSDONTMATCH": '502',
}

numeric_to_symbolic = {}
for k, v in symbolic_to_numeric.items():
    numeric_to_symbolic[v] = k
